Motor vehicles include warning systems for providing audible, visible or other warning indications to a motor vehicle operator of a problem condition related to the performance of the motor vehicle. Often, the warning system include s a display panel that has indicators for signaling of fault conditions. Each indicator traditionally has a single function, warning against a particular condition that has been detected by the warning system.
A conventional display panel is limited in size. As a practical matter, the number of faults that can be detected in the complex motor vehicles of today far exceed the amount of space available in a conventional display panel. In some motor vehicles, such as motorcycles, the size of the display panel is severely restricted. Accordingly, conventional warning systems group similar faults creating generalized system level warning indicators (e.g., oil pressure, temperature, battery etc.) Users are alerted to the system level event and respond in accordance with operator instructions. In general, the warning system provides rudimentary information that must be investigated further as to its ultimate cause and correction. While the information is rudimentary, the value is often quite significant. If the motor vehicle operator chooses to disregard the detected fault, permanent damage to the motor vehicle and/or its systems can result.
In one aspect, the invention provides a fault detector for determining a charge system fault in a motor vehicle charging system using an existing warning indicator on a display panel of the motor vehicle. The fault detector includes a charge isolator receiving as an input a signal indicative of the charge voltage provided from an alternator of the motor vehicle to the battery, a charge power loss detector operable to determine when a voltage level of the input signal is less than a predetermined threshold, a flasher operable to generate a pulsed signal if the voltage level of the in put signal is less than the predetermined threshold and signaling logic operable to transmit the pulsed signal to an existing warning indicator on a display panel of the motor vehicle, detect a fault associated with the existing warning signal and prioritize between the fault and the charge system fault including selecting a higher priority fault to drive the existing warning indicator.
Aspects of the invention can include one or more of the following features. The fault detector can include a flasher timer for controlling a duty cycle of the pulsed signal. The fault detector can include motor vehicle shut-off logic for detecting when the motor vehicle is not operating, and flasher power shut-off logic for shutting down the flasher when the motor vehicle is not operating. The fault detector can include a flasher amplifier operable to receive the pulsed signal and drive the existing warning indictor at a steady rate. The flasher can be an integrated circuit. The fault detector can be a CMOS integrated circuit operating as a monolithic timer in an a stable configuration. The motor vehicle can be a motorcycle, snowmobile, Altra-lite aircraft, or motorboat. The existing warning indicator can be a low oil pressure indicator. The charge isolator can be a rectifier isolation diode. The signaling logic can be operable to transmit the pulsed signal to an existing warning indicator on a display panel of the motor vehicle if a charge system fault is detected and disable the transmission of the pulsed signal to the existing warning signal if the fault associated with the existing warning indicator is detected. The fault associated with the existing warning indicator can be a low oil pressure fault. The oil pressure fault can have a higher priority than a charging system fault. The charger isolator can be operable to isolate the charging system from the motor vehicle""s load and a battery. The charger isolator can be operable to current limit received signals. The existing warning indicator can be selected from the group of a low oil pressure indicator, a high oil temperature indicator, a high water temperature indicator and a low fuel indicator.
In another aspect, the invention provides a method for detecting a charging system fault in a motor vehicle. The motor vehicle includes a low oil pressure warning indicator for indicating when oil pressure for the motor vehicle is too low. The method includes detecting a charge system fault, determining if the oil pressure is too low, and if so, driving the low oil pressure warning indicator with a first signal. If the oil pressure is within an acceptable range, and if a charging system fault is detected, the method includes driving the low oil pressure warning indicator with a second signal that is distinct from the first signal used to drive the low oil pressure warning indicator when oil pressure is too low.
In another aspect, the invention provides a method for detecting a charging system fault in a motor vehicle. The motor vehicle includes an existing warning indicator driven by a first signal for indicating when one aspect of the motor vehicle performance is faulty. The method includes detecting a charge system fault, determining if the one aspect of the motor vehicle""s performance is faulty and, if so, driving the existing warning indicator with the first signal. If the one aspect is not faulty and a charge system fault has been detected, the method includes driving the existing warning indicator with a second signal corresponding to the detected charge system fault. The second signal provides a different visual indication than the first signal.
Aspects of the invention can include one or more of the following advantages. A self-contained, hermetically sealed, alternator-charging system fault detector for any battery charging system is proposed. The battery charging system can be included on a motorcycle snowmobile, motorboat, Altra-lite aircraft and the like. The alternator-charging system utilizes existing vehicle wiring and fault displays. A fault detector uses a single, instrument panel mounted, indicator (e.g., low oil pressure light) for two operational meanings. In a first operational mode, the fault detector operates to detect an alternator low voltage output condition. Upon detecting the alternator low voltage output, the fault detector operates to cause the flashing of the (low oil pressure) indicator. In a second operational mode, when a loss of oil pressure is detected, the oil pressure indicator is illuminated steadily. Both of the fault modes indicate a very serious condition, however, the engine having low oil pressure is generally deemed to be of a more critical nature. A system is provided for prioritizing among the plurality of faults associated with a single fault indicator, and includes a priority indication to distinguish the higher priority fault in the event of a dual system failure.